how do roots of plants get oxygen for respiration
Plants respire through the tiny pores on the surface of their leaves called stomata . Oxygen enters the plant, while carbon dioxide leaves the plant through these pores. This exchange of gases occurs through the process of diffusion. When carbon dioxide is present in high concentration inside the plant body, it moves out into the atmosphere (where its concentration is low) and allows oxygen to enter the plants.
The roots of plants also respire. They do so by taking in oxygen from the air spaces present in soil. This oxygen enters the root hairs through diffusion and then it reaches other cells of roots for respiration. Carbon dioxide produced during respiration move outside through the root hairs in the same way by the process of diffusion.